Experts say when a trait you used to adore in your partner starts driving you away, it's a 'fatal attraction'

When Laurie Davis first met Thomas Edwards, she was attracted to how outgoing and confident he is. Ms. Davis, an introvert, had enjoyed solo picnics and beach outings. After the two began a relationship, her life filled up with barbecues, birthday parties and weekends in the mountains with other couples.

It was really exciting—at first. But Ms. Davis, who was starting an online-dating consulting business and working long hours, eventually tired of the constant socializing. She asked Mr. Edwards to spend more time at home...